The present invention is directed to a drill chuck for a hand-held device, such as a percussion drill, a drill hammer or the like for securing the shank of a tool. The drill chuck includes at least two clamping jaws supported in a chuck member so that the jaws can be radially displaced and adjusted to the diameter of the tool shank inserted into the chuck. A first sleeve is mounted on the chuck member and has a conically shaped surface in contact with the clamping jaws. The chuck member and the first sleeve are interconnected so that they do not rotate relative to one another but the first sleeve is axially displaceable relative to the chuck member. A second sleeve is connected with the first sleeve and is in threaded engagement with the chuck member. Gear teeth are formed on the second sleeve and a gear teeth key can be engaged with the teeth on the second sleeve for rotating the second sleeve about the chuck member.
Particularly in the field of percussion drills, drill chucks are known which have radially adjustable clamping jaws. As a rule, such clamping jaws are radially adjusted by a rotatable sleeve having a conical surface so that the jaws can receive and hold substantially cylindrically shaped shank ends of tools of various diameters. Since the tool shanks in such drill chucks are clamped only in a force-locking manner, such drill chucks are not suitable for drill hammers in which substantially higher stresses are developed. While in percussion drills only vibrational movement is transmitted to the tool shank, in drill hammers or chisel devices a hammering action is transmitted to the end of the tool shank. Accordingly, drill chucks which afford a form-locking engagement of the tool shank have been successful in drill hammers and chisel devices. In such chucks, radially adjustable elements cooperate with stop surfaces on the shank end of the tool. The full effectiveness of such devices can only be achieved when the tool shank is held in the chuck with a limited amount of play. Therefore, a relatively difficult task is imposed on the drill chuck in which the shank end of a tool is guided within the chuck and now requires radially adjustable elements for affording axial and radial support at corresponding stop faces on the tool shank. With regard to the tools, this problem led to providing extremely uneconomical dimensioning of the tools, since the shank end of the tool had to be provided which was either too large for smaller tool diameters or too small for larger tool diameters.